Hi Steve, No - the rest of the flex is ENIG- pads are for chips/caps/resistors and a BGA. I received a sample part from the customer this A.M. and am going to see if I can analyze the specific area because the design does not allow for electroplating most of the wire bond pads - (no via or outside connection) and I see no evidence of using the gold as an etch resist. Regards Steve -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Steven Creswick Sent: April-01-10 9:07 AM To: [log in to unmask] Subject: Re: [TN] Wire bondable gold Steve, Just to clarify my comments a bit more. I understand that the area you are speaking of is for wirebonding only. However, since the entire assembly is electroless Au plated, is there somewhere else where a wiping contact is being made [outside of the bonding area]? A good example from hybrid days is a hermetic coaxial connector. Needs to be mated/de-mated many times on the outside and wirebonded to on the inside. First apply the underlying Ni. Then, plate the center contact with electroless [hard] Au all over + soft gold all over, making it wirebondable on the inside and of reasonable durability on the outside. [did not have to be concerned with solderability] This is exactly what you have - and it has been around for a long time. Possibly someone is cutting & pasting from another not-so-applicable document...? Doesn't hurt to ask them what they are up to. Myself, given 150 µinches of Ni under 50 µinches of pure soft gold, I would nearly be in heaven bonding to it. I only wish I could have had that on some boards I've dealt with. Like being on a nice warm sunny beach with my beautiful wife in one hand and a nice cool drink in the other - it would not get much better! Depending upon prior processing conditions, they could likely get away with no more than 20-30 µinches and not even be aware of the reduction in soft gold thickness. Sometimes it is also a good thing to look at the amount of area actually being plated. If it is a small area, the cost differential between 30 & 50 µinches may not be all that great. If you were plating an entire 18 x 24" panel - well then, I wouldn't mind having the extra 20 µinches to help pay the bills. If not making a contactor somewhere else on the assy, I too do not understand why the e-less Au is needed. The 150 µin of Ni will do a great deal to prevent any Cu diffusion. As far as corrosion goes ... if the environment is THAT bad, why are you placing a bare [or glob topped, etc] die there? Be interesting to hear what kind of story you get back. Steve Creswick http://www.linkedin.com/in/stevencreswick ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________ --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________ --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------